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Nutrient Transport - Exercise #1

You are studying nutrient uptake in E. coli and are curious about the TrkG transporter.

  1. What molecule(s) does this transporter move into the cytosol and/or periplasmic space?  Establish what category (Passive Diffusion, Facilitated Diffusion, Active Transport).  Establish what class (Ion Driven – be specific, Group Translocation, ABC Transporter) of transporters it belongs to.  What energy source, if any, drives the uptake process?
  2.  

  3. What is the affinity of this transporter for its transported molecule(s)? 
  4.  

  5. Is the transcription of the transporter gene regulated?  If so, what protein(s) regulate it?
  6.  

  7. Is the transport activity of TrkG regulated by any protein(s) and/or molecule(s)?  Explain.
  8.  

  9. In which membrane is the transporter localized?  How many transmembrane helices does it have (Hint: Look at the Sequence Features diagram)?